The present invention relates to the formulation of a stable, hard surface detergent composition in the form of a non-pourable viscous cleaning composition, substantially free of water, i.e., having a maximum water content of 6% by weight, comprising a gelled mixture of an organic liquid vehicle consisting essentially of organic solvents and nonionic surfactants including an ethoxylated fatty acid as the essential component in the in situ gelation of said liquid vehicle, upon the addition of a small amount of about 0.7-1.5% by weight sodium hydroxide. The addition of gel-insoluble ingredients, particularly a water-soluble inorganic builder-abrasive, to the gel mixture forms a viscous paste product containing a stable suspension of the relatively large particles of said abrasive.
The abrasive is insoluble in the gel product, but soluble in water. Thus, after using this paste product to clean a hard surface, the water applied to rinse off the cleaning product dissolves both the gel and the abrasives, and leaves no gritty residue on or around the cleaned surfaces.
The prior art is replete with hard surface cleansers containing abrasives both in the form of scouring powders and in liquid form. Water insoluble abrasives as the major and primary cleaning component in scouring powder cleansers is well known, as disclosed in U.S. Pat. No. 3,850,833. However, the use of said water-insoluble abrasives in hard surface scouring powder cleansers has been found to leave an unpleasant gritty residue on the cleaned surface. This problem has been addressed in the prior art by substituting a water soluble abrasive for all or part of the insoluble abrasive, resulting in a composition wherein the water soluble components rinse away with the wash water, leaving substantially no residue on the cleaned surface, as disclosed in U.S. Pat. No. 3,577,347. Another method of addressing the abrasive residue problem is the use of a powdered or particulate water-insoluble abrasive having a maximum particle size under 0.15 mm., and about 8% by weight of the abrasive particle having a diameter of about 0.037 mm or larger for effective cleaning, and a small amount of an organic hydrotrope (i.e., sodium cumene sulfonate) to improve grease removal, as disclosed in U.S. Pat. No. 4,289,640.
Likewise, hard surface liquid detergent composition containing water-insoluble abrasives suspended in an aqueous medium encounter the problems of stability as well as the difficulty of complete removal of the insoluble abrasive particles from the cleaned surface. These problems have been addressed in the prior art preparing a heavy duty liquid detergent composition containing a water soluble builder salt having colloidal-size particles (below 1 micron and usually below 0.1 micron), dispersed in an aqueous medium containing a fatty acid amide emulsifying agent as disclosed in U.S. Pat. No. 4,057,506. Other means of addressing the stability problem is disclosed in U.S. Pat. No. 3,522,186 wherein is disclosed a water-insoluble abrasive dispersed in an aqueous medium containing tetrapotassium pyrophosphate, sodium soap, diethanolamide and about 0.25-1.5% methanol or ethanol to prevent the separation of the aqueous liquid into two layers. Another means of addressing the stability problem is disclosed in U.S. Pat. No. 4,051,055 wherein an aqueous hard surface cleaning composition containing water insoluble abrasive is suspended in a thickened aqueous medium with at least 1% clay as the thickening agent, said thickened system preventing separation of the abrasive from the liquid medium. The presence of fluoride salts enhances the ability of the clay-thickened system to hold the abrasive particles in suspension.
U.S. Pat. No. 4,657,692 also discloses a thickened aqueous scouring cleanser, free of syneresis (separation of solids from liquid), containing a water insoluble abrasive suspended in an aqueous medium containing a colloidal aluminum oxide thickener, water soluble alkali metal inorganic salts such as the phosphates, polyphosphates, carbonates, etc., and about 0.5-3% of a surfactant and a halogen bleach. European Patent Application No. 0.193,375 resorts to the use of a water soluble salt, which functions both as an abrasive and detergency builder, such as sodium bicarbonate, tripolyphosphate, and the like, in a pourable, homogenous abrasive-containing aqueous detergent composition for cleaning hard surfaces, and also containing a mixture of anionic and nonionic surfactants in the weight ratio of 1:1 to 9:1 anionic to nonionic surfactant.
A hard surface, water-based cleanser in paste form comprising 50-65% sodium bicarbonate and 50-35% by weight water containing sodium chloride and a fatty acid (C.sub.12 -C.sub.16) diethanolamide is disclosed in U.S. Pat. No. 4,179,414.
Water-based gels containing at least 40% nonionic surfactant and 2-10% water soluble builder salts is disclosed in U.S. Pat. No. 4,107,067 as a flowable gel laundry detergent composition.
U.S. Pat. No. 4,257,908 also discloses a laundry detergent composition in a stable flowable form, containing 25-55% of a phosphate builder salt, 5-40% of an anionic surfactant in 30-50% of an aqueous medium containing alcohol in the weight ratio of 5:1 to 20:1 water to alcohol.
Also, non-aqueous liquid pasty or gelatinous detergent compositions having scouring properties is disclosed in U.S. Pat. No. 3,981,826, comprising a dispersion of a normally solid water soluble anionic surfactant and a solid particulate water soluble inorganic salt (a builder salt) and a suspending agent such as highly-voluminous oxides (silica, magnesia, alumina or clay) in about 19-79% of a water-miscible organic liquid solvent such as a polyhyrdic alcohol (glycerol, ethylene glycol, and the like), and optionally a lower monohydric alcohol (ethanol, methanol, etc.). Another organic solvent-based gelled or thickened hard surface cleaning composition which is flowable and pourable is disclosed in U.S. Pat. No. 3,865,756 comprising a gelling agent which functions as an abrasive such as colloidal silica, an alkaline builder salt such as water soluble phosphates and silicantes, a surfactant, a water insoluble abrasive, i.e., calcium silicate, and about 55-90% of an organic cleaning solvent such as a major amount of an aliphatic hydrocarbon mineral spirit mixed with 4-7% ethylene glycol monobutyl ether. U.S. Pat. No. 2,864,770 also discloses a pourable non-aqueous water-soluble organic solvent-based thixotropic liquid detergent composition containing glycols and glycerol as the organic solvent, an anionic surfactant, and a phosphate builder in suspension.
However, none of the above mentioned patents disclose a hard surface non-pourable viscous cleaning composition, substantially free of water, comprising a gelled mixture of an organic liquid vehicle consisting essentially of water-soluble organic solvents and nonionic surfactants including an ethoxylated fatty acid as one of the surfactants, and a small amount of sodium hydroxide which reacts in situ with the ethoxylated fatty acid to form a clear organic, non-flowable gel, and about 10-25% of a water soluble builder-abrasive suspended in said gelled vehicle.